The present invention relates to a safety valve particularly but not exclusively for installation in a receiving connection (called a "nipple") of a production tube of a well, to shut off in this tube the passage of the effluent produced, e.g. oil or gas.
The safety valves used at the present time are provided with a locking system mounted on the upper part of the valve body to lock the latter in a stop groove in the receiving connection of the production tube, and with two sealing linings which are located underneath the locking system and which come up against two inner smooth bearing surfaces of the receiving connection, between which opens an inlet for the fluid for controlling the valve.
The disadvantage of this arrangement is that the safety valves constitute somewhat long components and that they substantially reduce the passage cross-section for the effluent, because their active part is located entirely under the stop groove of the receiving connection, that is to say in a narrowed portion of the latter. This results in considerable load losses. Additionally, the locking system is subjected to the corrosive action of the effluent.